Magnetic light-emitting structure and fabrication method for manufacturing a magnetic light-emitting element

ABSTRACT

A magnetic light-emitting structure and fabrication method for manufacturing a magnetic light-emitting element are provided. The fabrication method comprises providing a magnetic metal composite substrate, wherein a second metal layer is respectively disposed on an upper and lower surface of a first metal layer; forming a connecting metal layer, an epitaxial layer and a plurality of electrode unit on top; and performing a complex process, which removes the second metal layer on the lower surface of the first metal layer and part of the first metal layer and performs cutting according to the number of the electrode unit, so as to form a plurality of epitaxial die. Each epitaxial die corresponds to an electrode unit to form a magnetic light-emitting element. The proposed method improves soft magnetic properties of an original substrate and enables dies to reverse spontaneously, thereby used perfectly for industrial mass transfer technology.

This application claims priority for Taiwan patent application no.109126508 filed on 5 Aug. 2020, the content of which is incorporated byreference in its entirely.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a magnetic light-emitting structure anda fabrication method for manufacturing a magnetic light-emittingelement. More particularly, the magnetic light-emitting structure andfabrication method for manufacturing the magnetic light-emitting elementof the present invention are aimed to modify a magnetic metal compositesubstrate to comprising a vertical type light emitting diode die ofbetter soft magnetic properties and initial magnetic permeability.

Description of the Prior Art

In general, a Light Emitting diode (LED) is a kind of light source whichis fabricated using the semiconductor technology and formed by III-Vgroup compound semiconductors. The LEDs operate based on a fact thatelectrons are combined with holes in a semiconductor to produce photons.The LEDs are different from the conventional light bulbs working at ahigh temperature of thousands of degrees. The LEDs are also differentfrom fluorescent lamps using a high voltage to excite an electron beam.Just like a general electronic element, an LED only requires a voltageof 2˜4 V to operate and thus being able to work at a normal temperatureenvironment. Compared with the traditional tungsten light bulbs, LEDsare certainly advantageous of having longer lifetime, higher luminousefficiency, lower failure rate, saving more power, and giving much morestable light. Also, LEDs are highly compatible with various types oflamp devices. Therefore, the luminous life of LEDs is believed to bemuch longer than that of the traditional light sources, thereby the LEDshas successfully become a mainstream commodity in the market nowadays.

Overall, the LED structures mainly comprise a horizontal structure and avertical structure. Regarding a horizontal-structure LED, two electrodesof the horizontal-structure LED are arranged at the same side of the LEDchip. Nevertheless, two electrodes of a vertical-structure LED arerespectively arranged at two opposite sides of an epitaxial layer of theLED chip. In general, compared with the horizontal-structure LED, thevertical-structure LED has advantages of high brightness, rapid heatdissipation rate, small luminous decay and high stability. In view ofdevice structure, photoelectric parameter, thermal property, luminousdecay and fabrication cost, the vertical-structure LED always has muchbetter heat dissipation effect than the horizontal-structure LED. Due tothe great heat dissipation feature of the vertical-structure LED, theheat generated by the chip can always be dissipated in time, therebyminimizing the attenuation in performance of the chip and phosphor. As aresult, it is believed that the LEDs are successfully characterized byhigh brightness, rapid heat dissipation rate, small luminous decay, andless drift of light color and thus provides much more reliablestability.

However, it is known that LEDs have been widely applied in a variety oftechnical fields recently. For example, LEDs can be applied into a smartphone. And once the smart phone starts to overheat, the LED chipinstalled therein will also be affected. And then, the substrate used toplace the dies in the LED chip and to connect the smart phone or otherdevices will be affected as well. If such substrate has poor thermalexpansion coefficient, the substrate is very likely to bend and deformdue to the temperature changes, thereby influencing the lightingefficiency of the LED chip.

On the other hand, Micro LEDs are also regarded as an emergingtechnology after the miniaturization and matrixization of LEDs, whichcan integrate high-density and small-sized LED arrays on the wafer. Eachpixel therein can be addressed and individually driven to emit light.However, despite the continuous progress of Micro LEDs, themanufacturing cost of Micro LEDs, so far has remained very high, andthus affects its commercialization process. The main problem is that,the micro-assembly of “Mass Transfer” technology are not accomplished.In the prior arts, a manipulator to repeatedly reciprocate and gripindividual Micro LED chip one at one time is the only way to transferthe Micro LED chip onto the substrate. Such traditional operating methodtakes too much cost and time, which results in one of the majorbottlenecks of the current Micro LED to achieve mass transfer and causesenormously high production cost as well as excessive man-operatinghours.

Besides, in the traditional method to proceed with the mass transfer ofMicro LEDs, a flip-chip technology usually must be involved forreversing (flip-chipping) the die due to the few connection points(electrical pads) thereof. And such action also plays a complicated andredundant role in the process of the mass transfer of Micro LEDs and istherefore a serious issue to be overcome as well.

Therefore, on account of above, to overcome the abovementioned problems,it should be obvious that there is indeed an urgent need for theprofessionals in the field for a new magnetic light-emitting structureand a fabrication method for manufacturing a magnetic light-emittingelement to be developed that can effectively solve the above mentionedproblems occurring in the prior design. By using the proposedfabrication method, a composite substrate having low production cost,better soft magnetic properties, initial magnetic permeability, a highthermal conductivity and low thermal expansion coefficient isfabricated. Hereinafter, the detailed specific implementations will befully described in the following paragraphs.

SUMMARY OF THE INVENTION

In order to overcome the above mentioned disadvantages, one majorobjective in accordance with the present invention is provided for amagnetic light-emitting structure and a fabrication method formanufacturing a magnetic light-emitting element. The novel magneticlight-emitting element comprises a vertical type light emitting diodedie of great initial magnetic permeability, which is composed of asubstrate having soft magnetic properties and an epitaxial electrodelayer formed on the magnetic substrate. Owing to the extraordinary softmagnetic properties and initial magnetic permeability characterized bythe magnetic substrate disclosed by the present invention, the presentinvention is thus applicable to meeting the requirements for industrialmass transfer technological needs.

And yet, another major objective in accordance with the presentinvention is provided for a spontaneous automatic reversal effect due toa certain magnetic force difference between the upper layer (i.e. theepitaxial layer) and the lower layer (i.e. the nickel-iron alloy layer)of the magnetic light-emitting element. Such a magnetic force differenceenables each final crystal die to be able to perform automatic reversaleven when it was in a wrong direction in the first place. In this case,the nickel-iron alloy layer can always automatically turn down and in alower position of the structure, such that the optimal result ofautomatic alignment and positioning can be accomplished. Through thespontaneous automatic reversal effect of each die along with thesubsequent Micro LED mass transfer process, the present inventionachieves to avoid the conventional flip-chip process and operation stepsthereof. As a result, the traditional excessively high operating time,manpower, and production cost are effectively reduced, perfectly meetingthe requirements for industrial mass transfer technological needsnowadays.

For achieving the above mentioned objectives, the technical solutions ofthe present invention are aimed to provide a fabrication method formanufacturing a magnetic light-emitting element, comprising: providing amagnetic metal composite substrate, which comprises a first metal layerand two second metal layers, wherein each of the second metal layers isrespectively disposed on an upper surface and a lower surface of thefirst metal layer; then forming a connecting metal layer on the magneticmetal composite substrate and an epitaxial layer on the connecting metallayer; next, providing a plurality of electrode unit on a top surface ofthe epitaxial layer; and performing a complex process, which comprisesremoving the second metal layer which is located on the lower surface ofthe first metal layer and part of the first metal layer as well asperforming cutting according to the number of the plurality of electrodeunit, so as to form a plurality of epitaxial die. Each the epitaxial diecorresponds to each the electrode unit to form one magneticlight-emitting element according to each the epitaxial die.

An another aspect of the present invention is to show that the magneticlight-emitting element fabricated by the present invention can befurther adhesively connected to an adhesive material layer through theepitaxial layer to maintain the integrity of the die and protect it frombeing damaged. Furthermore, using the adhesive material layer also helpsto improve the subsequent cutting quality of the die and the convenienceof grabbing the die. In one embodiment of the present invention, theproposed adhesive material layer can be, for instance a blue tape or aUV tape.

In addition, according to one embodiment of the present invention, amaterial of the first metal layer in the magnetic metal compositesubstrate, for example, can be nickel-iron alloy (Invar). And, amaterial of the second metal layer in the magnetic metal compositesubstrate is copper. A thickness proportion of the second metal layer tothe first metal layer to the second metal layer in the magnetic metalcomposite substrate ranges from 1:3:1 to 1:9:1. The second metal layer,the first metal layer and the second metal layer therein the magneticmetal composite substrate can be combined through cutting, vacuumheating, and grinding or polishing to form the magnetic metal compositesubstrate, such that the magnetic metal composite substrate has a highthermal conductivity, low thermal expansion coefficient and initialmagnetic permeability. As one illustrative example, according to theembodiment of the present invention, the magnetic metal compositesubstrate formed by the present invention may have a thickness of 30microns to 50 microns.

Furthermore, according to the complex process disclosed in oneembodiment of the present invention, the complex process may comprisethe following steps:

1. performing a cutting process, in which the cutting process performsdividing according to the number of the plurality of electrode unit. Thecutting process is applied to the epitaxial layer, the connecting metallayer and the magnetic metal composite substrate to form the pluralityof epitaxial die, such that each the epitaxial die corresponds to eachthe electrode unit. The cutting process includes a cutting end point,and the cutting end point is configured in the first metal layer of themagnetic metal composite substrate; and

2. performing an etching process, which removes the second metal layerwhich is located on the lower surface of the first metal layer and partof the first metal layer, such that the magnetic light-emitting elementis formed according to each the epitaxial die.

Alternatively, according to the complex process disclosed in anotherembodiment of the present invention, the complex process may comprisethe following steps:

1. performing an etching process, which removes the second metal layerwhich is located on the lower surface of the first metal layer and partof the first metal layer; and

2. performing a cutting process, in which the cutting process performsdividing according to the number of the plurality of electrode unit. Thecutting process is applied to the epitaxial layer, the connecting metallayer, the second metal layer which is located on the upper surface ofthe first metal layer and the remaining first metal layer to form theplurality of epitaxial die, such that each the epitaxial die correspondsto each the electrode unit, and the magnetic light-emitting element isformed according to each the epitaxial die.

Among the foregoing two various embodiments disclosed by the presentinvention, the proposed cutting process can be implemented through alaser cutting, having its laser wavelength in a range of 355 nm to 532nm. A cutting depth is made to be 30 microns to 50 microns.

Also, according to the two embodiments disclosed by the presentinvention, the proposed etching process can be implemented through a wetchemical etching process, in which an etching time for the wet chemicaletching process is 10 minutes, and an etching solution is alternativelya ferric chloride solution, a mixture of nitric acid (HNO₃) and hydrogenperoxide (H₂O₂), or a mixture of sulfuric acid (H₂SO₄) and hydrogenperoxide (H₂O₂), wherein the ratio of nitric acid to hydrogen peroxidefor example, can be 3:1, and the ratio of sulfuric acid to hydrogenperoxide can be 4:1.

In yet another aspect, the present invention further provides a magneticlight-emitting structure, comprising: a magnetic metal compositesubstrate; a connecting metal layer, being disposed on the magneticmetal composite substrate; an epitaxial layer, being disposed on theconnecting metal layer; a plurality of electrode unit, being disposed ona top surface of the epitaxial layer; a titanium layer, being disposedon a lower surface of the magnetic metal composite substrate; and a goldlayer, being disposed on a lower surface of the titanium layer. In theembodiment, the disclosed magnetic metal composite substrate includes afirst metal layer and a second metal layer which is disposed on an uppersurface of the first metal layer.

According to such an embodiment, a material of the first metal layer inthe magnetic metal composite substrate, for example, can be nickel-ironalloy (Invar). And, a material of the second metal layer in the magneticmetal composite substrate is copper.

Moreover, according to such an embodiment, a thickness of the titaniumlayer, for example, can be 0.5 μm. A thickness of the gold layer can be1.0 μm.

These and other objectives of the present invention will become obviousto those of ordinary skill in the art after reading the followingdetailed description of preferred embodiments.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary, and are intended toprovide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the invention, and are incorporated in and constitute apart of this specification. The drawings illustrate embodiments of theinvention and, together with the description, serve to explain theprinciples of the invention. In the drawings:

FIG. 1 shows a flow chart of a fabrication method for manufacturing amagnetic light-emitting element in accordance with an embodiment of thepresent invention.

FIG. 2 shows a structural diagram of a magnetic metal compositesubstrate in accordance with the embodiment of the present invention.

FIG. 3 shows a structural diagram of forming a connecting metal layer,an epitaxial layer and a plurality of electrode unit on top of themagnetic metal composite substrate in accordance with the embodiment ofthe present invention.

FIG. 4 shows a flow chart of performing the step S15 according to oneembodiment of the present invention.

FIG. 5 shows a schematic diagram of the device structure in FIG. 3 whenperforming a cutting process.

FIG. 6 shows a schematic diagram of the device structure in FIG. 5 afterthe cutting process is complete.

FIG. 7 shows a schematic diagram of the device structure in FIG. 6 whenperforming an etching process.

FIG. 8 shows a schematic diagram of the device structure in FIG. 7 afterthe etching process is complete.

FIG. 9 shows a schematic diagram of the magnetic light-emitting elementwhich is further connected to an adhesive material layer in accordancewith the embodiment of the present invention.

FIG. 10 shows a flow chart of performing the step S15 according toanother embodiment of the present invention.

FIG. 11 shows a schematic diagram of the device structure in FIG. 3 whenperforming an etching process.

FIG. 12 shows a schematic diagram of the device structure in FIG. 11after the etching process is complete.

FIG. 13 shows a schematic diagram of the device structure in FIG. 12when performing a cutting process.

FIG. 14 shows a schematic diagram of the device structure in FIG. 13after the cutting process is complete.

FIG. 15 shows a schematic diagram of a magnetic light-emitting structurein accordance with one embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers are used in thedrawings and the description to refer to the same or like parts.

The embodiments described below are illustrated to demonstrate thetechnical contents and characteristics of the present invention and toenable the persons skilled in the art to understand, make, and use thepresent invention. However, it shall be noticed that, it is not intendedto limit the scope of the present invention. Therefore, any equivalentmodification or variation according to the spirit of the presentinvention is to be also included within the scope of the presentinvention.

In view of the various deficiencies disclosed by the above mentionedprior arts, the present invention is aimed to provide a fabricationmethod for manufacturing a magnetic light-emitting element. Byfabricating the vertical type light emitting diode die on a substratehaving initial magnetic permeability and better soft magneticproperties, the present invention is able to employ the speciallydesigned substrate with soft magnetic properties and the mechanism ofmagnetic array absorption to comply with the requirements of Micro LEDfor rapid mass transfer, whereby effectively solves the drawbacks ofconventional Micro LED whose manufacturing cost and process areenormously high and complicated.

In addition, due to the magnetic force difference between the upper andlower layers of the substrate, the present invention is aimed to ensurethat each final crystal die is able to perform automatic reversal evenwhen it was in a wrong direction in the first place. Therefore, thealignment of the die distribution position is controlled to be accurate.By using such design manners, the present invention effectively solvesthe conventional problems of excessively high operating time, manpower,and production cost that had been existing in the traditional flip-chipbonding process in the past.

First, please refer to FIG. 1 . FIG. 1 shows a flow chart of afabrication method for manufacturing a magnetic light-emitting elementin accordance with an embodiment of the present invention, in which thefabrication method disclosed in the present invention comprises thesteps of S10, S12, S13 and S15. In the following paragraphs, thedetailed descriptions of the disclosed fabrication method of the presentinvention will be fully provided, and referred accompanying with thestructure and component symbols as shown in FIG. 2 to FIG. 14 .

Please refer to S10. In step S10 of the present invention, a magneticmetal composite substrate 200 is provided in the beginning. The magneticmetal composite substrate 200 comprises a first metal layer 21 and twosecond metal layers 22. Each of the second metal layers 22 isrespectively disposed on an upper surface and a lower surface of thefirst metal layer 21 (shown in FIG. 2 ). According to the embodiment ofthe present invention, the material of the first metal layer 21 is anickel-iron alloy, and the alloy may be, for example, a nickel-ironalloy having a nickel content of 36%. The material of the second metallayer 22 is copper. A thickness ratio of the first metal layer 21 to thesecond metal layer 22 is 3˜9:1, so the magnetic metal compositesubstrate 200 is formed, comprising the second metal layer 22, the firstmetal layer 21 and the second metal layer 22 from bottom to top and thethickness proportion of the second metal layer 22 to the first metallayer 21 to the second metal layer 22 ranges from 1:3:1 to 1:9:1.Preferably, the thickness proportion of the second metal layer 22 to thefirst metal layer 21 to the second metal layer 22 can be 1:5:1.According to the embodiment of the present invention, it is explanatoryto illustrate the first metal layer 21 and the second metal layer 22 asa nickel-iron alloy layer and a copper layer, respectively. For example,the thickness of the first metal layer 21 (nickel-iron alloy layer) maypreferably be 50 micrometers (μm), and the thickness of the second metallayer 22 (copper layer) may preferably be 10 micrometers (μm). However,the present invention is certainly not limited thereto such dimensionsand sizes.

Since the first metal layer 21 and the second metal layer 22 disclosedby the present invention can be combined through cutting, vacuumheating, and grinding or polishing to form the magnetic metal compositesubstrate 200, the formed magnetic metal composite substrate 200 is ableto be characterized by not only a superior initial magneticpermeability, but also a high thermal conductivity and low thermalexpansion coefficient. Accordingly, in the subsequent wire bonding andpackaging process, it helps to provide better production yield. Andcompared to the other conventional metal substrates, the production costof such magnetic metal composite substrate 200 can be much lower, andthe thickness is thinner as well. As a result, it indeed offers as a newtype of substrate having extremely low thermal expansion coefficient,high thermal conductivity, low production cost, and high yield withoutthe need of any additional thinning process. In addition, such novelmagnetic metal composite substrate is also easy to be bonded with anepitaxial layer.

Next, as shown in step S12. A connecting metal layer 202 is disposed onthe magnetic metal composite substrate 200, and an epitaxial layer 204is further disposed on the connecting metal layer 202 (shown in FIG. 3). According to the embodiment of the present invention, the connectingmetal layer 202 may further include a contact layer, a reflection layer,and a current distribution layer (not shown). The contact layer isdisposed on the magnetic metal composite substrate 200, the reflectionlayer is disposed on the contact layer, and the current distributionlayer is disposed on the reflection layer. Finally, the epitaxial layer204 is provided on the current distribution layer. According to theembodiment, the contact layer, for example, can be a P-type contact, thereflection layer, for example, can be, a Reflector, and the currentdistribution layer can be a P-type GaP layer.

Similarly, the epitaxial layer 204 may further include a first AluminumGallium Indium Phosphide (AlGaInP) layer, a Multiple quantum wells(MQWs) layer, a second Aluminum Gallium Indium Phosphide (AlGaInP)layer, a Gallium arsenide (GaAs) layer and so on (not shown). Forinstance, in one embodiment of the present invention, the first AlGaInPlayer can be a P-type AlGaInP layer, the second AlGaInP layer can be anN-type AlGaInP layer, and the GaAs layer can be an N-type GaAs layer.

Later, as shown in step S13 and FIG. 3 of the present invention, afterthe connecting metal layer 202 and the epitaxial layer 204 are provided,a plurality of electrode unit 18 are disposed on a top surface of theepitaxial layer 204 by an annealing process. The alloy of Au and Ge ismixed with Au by the annealing process at a temperature of 360 degreesto form the electrode units 18, wherein the ratio of the alloy of Au andGe to Au is 2:3 in amount. It is worth noticing that the cross-sectionalschematic diagram shown in FIG. 3 merely shows two electrode units 18for an explanatory embodiment of the present invention. However, thepresent invention is not limited thereto. According to the presentinvention, the number of the electrode units 18 can be configuredaccording to various specification requirements, for example, can beplural as well.

Next, as shown in step S15. A complex process is performed, in which thecomplex process comprises removing the first, second metal layers of themagnetic metal composite substrate 200 and performing cutting accordingto the number of the electrode unit 18, so as to form a plurality ofepitaxial die. Each epitaxial die corresponds to an electrode unit 18 toform a magnetic light-emitting element.

According to the present invention, it is worth noticing that in stepS15 of the invention, it is practicable to (1) removing the second metallayer 22 and part of the first metal layer 21 of the magnetic metalcomposite substrate 200 first, and (2) performing cutting according tothe number of the electrode unit 18.

Optionally, in step S15 of the invention, it is also practicable to (1)performing cutting according to the number of the electrode unit 18first, and (2) removing the second metal layer 22 and part of the firstmetal layer 21 of the magnetic metal composite substrate 200.

Hereinafter, the present invention is providing various embodiments forthese two implementation models, which will be described in detail asfollows.

At first, please refer to FIG. 4 , which shows a flow chart ofperforming the step S15 according to one embodiment of the presentinvention. As illustrated, the step S15 may comprise performing (1) thestep S141, and then (2) the step S143. The step S141 comprisesperforming a cutting process, and the cutting process includes a cuttingend point. Please refer to the device structure in FIG. 3 at the sametime. The cutting end point is configured in the first metal layer 21 ofthe magnetic metal composite substrate 200. Afterwards, the step S143 isperformed, which comprises performing an etching process, so as toremove the second metal layer 22, which is located on the lower surfaceof the first metal layer 21, and part of the first metal layer 21 toform the magnetic light-emitting element.

Specifically, please refer to FIG. 5 and FIG. 6 , in which the cuttingprocess LS performs dividing according to the number of the plurality ofthe electrode unit 18. The cutting process LS is applied to theepitaxial layer 204, the connecting metal layer 202 and the magneticmetal composite substrate 200 to form a plurality of epitaxial die 15,such that each epitaxial die 15 corresponds to an electrode unit 18. Itshould be noticed that the cutting process shown in FIG. 5 and FIG. 6 isreferred to the device structure in FIG. 3 . Thus, merely threeepitaxial dies 15 are demonstrated. Nevertheless, the present inventionis not limited thereto. People who are skilled in the art are able toperform dividing according to the number of the electrode units 18 so asto adjust the number of the epitaxial die 15 to be formed based on theactual needs for their final products. According to the presentinvention, the cutting process LS includes a cutting end point ST1. Asshown in FIG. 6 , the cutting end point ST1 is configured in the firstmetal layer 21 of the magnetic metal composite substrate 200. In theembodiment of the present invention, the foregoing cutting process LSfor example may be implemented through a laser cutting, in which thewavelength of the laser can be, for example, 355 nm to 532 nm,preferably 375 nm, the power supply is 5 watts, the frequency is 50 KHz,and the scanning rate is 100 cm/s. The laser cutting process isperformed at scanning of 50 times, and the cutting depth is 30 to 50microns. In addition, the cutting process LS in step S141 of the presentinvention can further be implemented through a pico-second laser or afemto-second laser. Compared to a traditional laser cutting, the cuttingaccuracy and precision of using pico-second lasers or femto-secondlasers are higher than those of using traditional cutting techniques.Applying pico-second lasers or femto-second lasers helps to maintain amuch more complete and sufficient area of epitaxial layer when formingepitaxial crystal dies, which is one major advantage of the presentinvention using pico-second laser or femto-second laser to performcutting process.

Then, with referring to the step S143, an etching process EH isperformed (shown in FIG. 7 ). As illustrated, the etching process EHremoves the second metal layer 22, which is located on the lower surfaceof the first metal layer 21, and part of the first metal layer 21 so asto form the magnetic light-emitting element 17, each corresponding toone epitaxial die as shown in FIG. 8 . Therefore, it is apparent thatthe magnetic light-emitting element 17 formed through the fabricationmethod disclosed by the present invention comprises the electrode unit18, the epitaxial layer 204, the connecting metal layer 202 and athinner magnetic metal composite substrate 200′. Such magnetic metalcomposite substrate 200′ only includes a second metal layers 22 which isdisposed on an upper surface of the first metal layer 21, and a thinnerfirst metal layer 21. As such, by employing the novel fabrication methodand etching process, the present invention modifies the conventionalsubstrate structure to make it have better soft magnetic properties andinitial magnetic permeability. Meanwhile, the magnetic light-emittingelement 17 formed in the present invention is applicable to microapplication levels, having its size less than 100 μm and able to meetthe current trend requirements for miniaturization of light-emittingcomponents in the industry.

As a result, when the magnetic light-emitting element 17 is employedwith wire bonding and packaging to form a vertical type light emittingdiode die, such vertical type light emitting diode die is able to havegreat initial magnetic permeability. Moreover, due to the initialmagnetic permeability of this novel and thinner magnetic metal compositesubstrate 200′, the magnetic metal composite substrate 200′ achieves togenerate a micro current and transmit the micro current to the epitaxiallayer 204. As a result, after the vertical type light emitting diode dieformed by the present invention is assembled into a diode module, it isfunctional for not only wireless electricity generation, but also newapplications of wireless light emission, whereby fully meet thepractical requirements of high-power light emitting diodes nowadays.

According to the embodiment of the present invention, the etchingprocess EH can be implemented through a wet chemical etching process, inwhich the etching solution can be, for example, a ferric chloridesolution, a mixture of nitric acid (HNO₃) and hydrogen peroxide (H₂O₂),or a mixture of sulfuric acid (H₂SO₄) and hydrogen peroxide (H₂O₂),where the ratio of nitric acid to hydrogen peroxide for example, can be3:1, and the ratio of sulfuric acid to hydrogen peroxide can be 4:1. Inthe embodiment, the etching time for the wet chemical etching process is10 minutes. And an etching rate of the wet chemical etching process,regarding the copper layer (i.e. the second metal layer 22), is 1.0micrometers per minute, while the etching rate of the wet chemicaletching process, regarding the nickel-iron alloy layer (i.e. the firstmetal layer 21), is 0.1 to 0.5 micrometers per minute. The presentinvention is aimed to use the etching process EH (step S143) to form thethinner magnetic metal composite substrate 200′, which accordingly hasexcellent soft magnetic properties and initial magnetic permeability.

And furthermore, in another aspect, due to the magnetic force differencebetween the epitaxial layer and the nickel-iron alloy layer, the presentinvention effectively employs the magnetic force difference between theupper and lower layers of the magnetic metal composite substrate, suchthat each final crystal die is able to perform automatic reversal evenwhen it was in a wrong direction in the first place. In this case, thenickel-iron alloy layer can always automatically turn down, so thealignment of the die distribution position will be accurate. Throughsuch design manners, the present invention successfully solves theconventional problems of excessively high operating time, manpower, andproduction cost that must had be used for the traditional flip-chipbonding process before. And thus, an optimal design of the presentinvention is accomplished.

Moreover, since the magnetic metal composite substrate disclosed in thepresent invention can use itself as a magnetic conductive structure, dueto its own soft magnetic properties, when this magnetic force is used tomass transfer to the printed circuit board (PCB) along with the abovementioned die-automatic reversal effect, the luminous intensity of eachdie can be individually controlled by grounding its upper electrode andcontrolling the voltage level of the circuit board via an integratedcircuit integrated (IC) chip. In addition, when it comes to furtherintegration onto a display panel, the purposes of controlling thepartitioned light of the display panel or controlling its differentluminous intensities can both be achieved, whereby greatly improve thecompetitiveness of its industrial developments in the future.

FIG. 9 shows a schematic diagram of the magnetic light-emitting elementwhich is further connected to an adhesive material layer in accordancewith the embodiment of the present invention. As shown in FIG. 9 , themagnetic light-emitting element fabricated in the present invention canbe employed with wire bonding and packaging to form a vertical typelight emitting diode die, and the epitaxial layer 204 can be adhesivelyconnected to an adhesive material layer 800. According to the embodimentof the present invention, the adhesive material layer 800 can be, forexample, a blue tape or a UV tape. In specific, the blue tape and the UVtape can be specially applied to protect the front surface of the waferduring grinding or cutting processes and shipping the wafers. Ingrinding process, the tapes protect the front surface of the wafer frombeing damaged and absorb the impact force therein, so as to ensure thatthe wafer will not crack. Furthermore, when dicing the wafer, using theblue tape or the UV tape also helps to fix the die stably on the tapewithout causing die loss, and thus improve the cutting quality as wellas the convenience of grabbing the die. At the same time, for a varietyof working objects or wafer types, various tapes having differentstickiness and yet no adhesive residue can also be adopted.

On the other hand, please refer to FIG. 10 , which shows a flow chart ofperforming the step S15 according to another embodiment of the presentinvention. As illustrated, in another embodiment of the presentinvention, the step S15 may alternatively comprise performing (1) thestep S151, and then (2) the step S153. The step S151 comprisesperforming an etching process. Please refer to the device structure inFIG. 3 at the same time. The etching process removes the second metallayer 22, which is located on the lower surface of the first metal layer21, and part of the first metal layer 21. Afterwards, the step S153 isperformed, which comprises a cutting process as to perform dividingaccording to the number of the plurality of the electrode unit 18 suchthat a plurality of epitaxial die is formed. Each epitaxial diecorresponds to an electrode unit, and accordingly the magneticlight-emitting element is manufactured.

Specifically, please refer to FIG. 11 and FIG. 12 . After the devicestructure in FIG. 3 is provided (including the magnetic metal compositesubstrate 200, the connecting metal layer 202, the epitaxial layer 204and the electrode units 18), the present invention continues to executethe complex process as shown in the step S15. And yet, in suchembodiment, the complex process comprises performing the step S151first, and then performing the step S153. As referring to FIG. 11 , theetching process EH is performed to remove the second metal layer 22,which is located on the lower surface of the first metal layer 21, andpart of the first metal layer 21 of the magnetic metal compositesubstrate 200. After the etching process EH in step S151 is done, thedevice structure is shown as in FIG. 12 . As described earlier, thepresent invention successfully employs such an etching process EH toform a thinner magnetic metal composite substrate 200′, which iseffectively characterized by excellent soft magnetic properties andinitial magnetic permeability.

Among them, the etching solution and solution ratio, etching time andother parameters of the etching process EH are as described in theprevious embodiment of the invention, so the same descriptions are notto be repeated here again.

Next, as shown in FIG. 13 , the cutting process LS in step S153 issubsequently performed. The cutting process LS performs dividingaccording to the number of the plurality of the electrode unit 18, andthe cutting process LS is applied to the epitaxial layer 204, theconnecting metal layer 202, the second metal layer 22 on an uppersurface of the first metal layer 21 and the remaining first metal layer21 so as to form a plurality of epitaxial die 15. As such, eachepitaxial die 15 corresponds to an electrode unit 18. Afterwards, whenthe cutting process LS is complete, please refer to FIG. 14 , themagnetic light-emitting elements 17, each corresponding to one epitaxialdie 15 are fabricated by the present invention.

According to the embodiment of the present invention, the cuttingprocess LS to be applied can be a laser cutting, for instance using theforegoing pico-second laser or femto-second laser techniques. Thedetailed process conditions, wavelength of the laser light, appliedpower, and other parameters of the cutting process LS are also asdescribed in the previous embodiment of the invention, so the presentinvention spares the same descriptions.

Therefore, to sum up, based on a variety of embodiments and technicalsolutions disclosed by the present invention, people who are skilled inthe art are allowed to adjust and make modifications according to theiractual production needs without departing from the spirits of theinvention, and yet still fall within the scope of the present invention.The several illustrative examples of the present invention illustratedin the earlier paragraphs are intended to explain the main technicalfeatures of the present invention so that those skilled in the art areable to understand and implement accordingly. Nevertheless, the presentinvention is definitely not limited thereto.

In a further aspect, please refer to FIG. 15 , which shows a schematicdiagram of a magnetic light-emitting structure in accordance with oneembodiment of the present invention. As shown, the magneticlight-emitting structure 11 comprises a magnetic metal compositesubstrate 200 a, a connecting metal layer 202, an epitaxial layer 204, aplurality of electrode unit 18, a titanium layer 208 and a gold layer210. The magnetic metal composite substrate 200 a only includes a firstmetal layer 21 and a second metal layer 22 which is disposed on an uppersurface of the first metal layer 21. According to the embodiment of thepresent invention, the material of the first metal layer 21 is anickel-iron alloy, and the alloy may be, for example, a nickel-ironalloy having a nickel content of 36%. The material of the second metallayer 22 is copper.

The connecting metal layer 202 is disposed on the magnetic metalcomposite substrate 200 a, and the epitaxial layer 204 is furtherdisposed on the connecting metal layer 202. The plurality of electrodeunits 18 are disposed on a top surface of the epitaxial layer 204. Thetitanium layer 208 is disposed on a lower surface of the first metallayer 21. The gold layer 210 is disposed on a lower surface of thetitanium layer 208. In such an embodiment, a thickness of the titaniumlayer 208, for example, can be 0.5 μm. And, a thickness of the goldlayer 210 can be 1.0 μm. According to the embodiment of the presentinvention, the above mentioned cutting process LS and etching process EHmay also be applied to the magnetic light-emitting structure 11 so as toform a plurality of magnetic light-emitting element. What differs fromthe foregoing embodiments is that, the magnetic light-emitting elementfabricated herein further comprises a titanium layer 208 and a goldlayer 210, which are configured on a lower surface of the first metallayer 21 (nickel-iron alloy layer).

Therefore, to sum above, it is apparent that, the present inventionproposes a novel magnetic light-emitting structure and a fabricationmethod for manufacturing a magnetic light-emitting, which modifies theoriginal grain substrate structure and materials to have better softmagnetic properties and initial magnetic permeability. As a result, thelight-emitting diode die itself can be taken as a magnetic conductivestructure. As long as it is assembled with a magnetic device, such as atiny magnetic probe, by employing the mechanism of magnetic arrayabsorption, a great number of vertical light-emitting diode diestructure having such soft magnetic properties can be absorbed at onetime to achieve rapid and mass-transfer efficiency. It also meets therequirements of the current Micro LED technology for rapid masstransfer, effectively enhancing its industrial productioncompetitiveness.

Meanwhile, another major objective of the present invention is toprovide a spontaneous automatic reversal effect due to a certainmagnetic force difference between the upper layer (i.e. the epitaxiallayer) and the lower layer (i.e. the nickel-iron alloy layer) of themagnetic light-emitting element. Such a magnetic force differenceenables each final crystal die to be able to perform automatic reversaleven when it was in a wrong direction in the first place. In this case,the nickel-iron alloy layer can always automatically turn down and in alower position of the structure, such that the optimal result ofautomatic alignment and positioning can be accomplished. And the rapidmass transfer in the related industry is also achieved. As a result, theApplicants assert that the present invention is instinct, effective andhighly competitive for incoming technologies, industries and researchesdeveloped in the future. It is obvious that the technical features,means and effects achieved by the present invention are significantlydifferent from the current solutions, and can not be accomplished easilyby those who are familiar with the industry. As a result, it is believedthat the present invention is indeed characterized by patentability andshall be patentable soon in a near future.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the present inventionwithout departing from the scope or spirit of the invention. In view ofthe foregoing, it is intended that the present invention covermodifications and variations of this invention provided they fall withinthe scope of the invention and its equivalent.

What is claimed is:
 1. A fabrication method for manufacturing a magneticlight-emitting element, comprising: providing a magnetic metal compositesubstrate, comprising a first metal layer and two second metal layers,wherein each of the second metal layers is respectively disposed on anupper surface and a lower surface of the first metal layer; forming aconnecting metal layer on the magnetic metal composite substrate and anepitaxial layer on the connecting metal layer; providing a plurality ofelectrode unit on a top surface of the epitaxial layer; and performing acomplex process, which comprises removing the second metal layer whichis located on the lower surface of the first metal layer and part of thefirst metal layer as well as performing cutting according to the numberof the plurality of electrode unit, so as to form a plurality ofepitaxial die, wherein each the epitaxial die corresponds to each theelectrode unit to form the magnetic light-emitting element according toeach the epitaxial die.
 2. The fabrication method for manufacturing amagnetic light-emitting element of claim 1, wherein the magneticlight-emitting element is employed with wire bonding and packaging toform a vertical type light emitting diode die, and the vertical typelight emitting diode die is able to have an initial magneticpermeability.
 3. The fabrication method for manufacturing a magneticlight-emitting element of claim 2, wherein the magnetic metal compositesubstrate generates a micro current and transmits the micro current tothe epitaxial layer due to the initial magnetic permeability.
 4. Thefabrication method for manufacturing a magnetic light-emitting elementof claim 2, wherein the first metal layer and the second metal layer arecombined through cutting, vacuum heating, and grinding or polishing toform the magnetic metal composite substrate, such that the magneticmetal composite substrate has a high thermal conductivity, low thermalexpansion coefficient and the initial magnetic permeability.
 5. Thefabrication method for manufacturing a magnetic light-emitting elementof claim 1, wherein a thickness proportion of the second metal layer tothe first metal layer to the second metal layer in the magnetic metalcomposite substrate ranges from 1:3:1 to 1:9:1.
 6. The fabricationmethod for manufacturing a magnetic light-emitting element of claim 1,wherein a material of the first metal layer in the magnetic metalcomposite substrate is nickel-iron alloy.
 7. The fabrication method formanufacturing a magnetic light-emitting element of claim 1, wherein amaterial of the second metal layer in the magnetic metal compositesubstrate is copper.
 8. The fabrication method for manufacturing amagnetic light-emitting element of claim 1, wherein the complex processcomprises: performing a cutting process, in which the cutting processperforms dividing according to the number of the plurality of electrodeunit, the cutting process is applied to the epitaxial layer, theconnecting metal layer and the magnetic metal composite substrate toform the plurality of epitaxial die, such that each the epitaxial diecorresponds to each the electrode unit, the cutting process includes acutting end point, and the cutting end point is configured in the firstmetal layer of the magnetic metal composite substrate; and performing anetching process, which removes the second metal layer which is locatedon the lower surface of the first metal layer and part of the firstmetal layer, such that the magnetic light-emitting element is formedaccording to each the epitaxial die.
 9. The fabrication method formanufacturing a magnetic light-emitting element of claim 8, wherein thecutting process is implemented through a laser cutting.
 10. Thefabrication method for manufacturing a magnetic light-emitting elementof claim 9, wherein a laser wavelength of the laser cutting is 355 nm to532 nm, and a cutting depth is 30 microns to 50 microns.
 11. Thefabrication method for manufacturing a magnetic light-emitting elementof claim 8, wherein the etching process is implemented through a wetchemical etching process.
 12. The fabrication method for manufacturing amagnetic light-emitting element of claim 11, wherein an etching time forthe wet chemical etching process is 10 minutes, and an etching solutionis a ferric chloride solution, a mixture of nitric acid (HNO₃) andhydrogen peroxide (H₂O₂), or a mixture of sulfuric acid (H₂SO₄) andhydrogen peroxide (H₂O₂).
 13. The fabrication method for manufacturing amagnetic light-emitting element of claim 1, wherein the complex processcomprises: performing an etching process, which removes the second metallayer which is located on the lower surface of the first metal layer andpart of the first metal layer; and performing a cutting process, inwhich the cutting process performs dividing according to the number ofthe plurality of electrode unit, the cutting process is applied to theepitaxial layer, the connecting metal layer, the second metal layerwhich is located on the upper surface of the first metal layer and theremaining first metal layer to form the plurality of epitaxial die, suchthat each the epitaxial die corresponds to each the electrode unit, andthe magnetic light-emitting element is formed according to each theepitaxial die.
 14. The fabrication method for manufacturing a magneticlight-emitting element of claim 13, wherein the cutting process isimplemented through a laser cutting.
 15. The fabrication method formanufacturing a magnetic light-emitting element of claim 14, wherein alaser wavelength of the laser cutting is 355 nm to 532 nm, and a cuttingdepth is 30 microns to 50 microns.
 16. The fabrication method formanufacturing a magnetic light-emitting element of claim 13, wherein theetching process is implemented through a wet chemical etching process.17. The fabrication method for manufacturing a magnetic light-emittingelement of claim 16, wherein an etching time for the wet chemicaletching process is 10 minutes, and an etching solution is a ferricchloride solution, a mixture of nitric acid (HNO₃) and hydrogen peroxide(H₂O₂), or a mixture of sulfuric acid (H₂SO₄) and hydrogen peroxide(H₂O₂).